A DNA Damage-Repair Dynamic Model for HRS/IRR Effects of C.elegans Induced by Neutron Irradiation.

Neutron irradiation which could trigger severe biological effects, is being applied in nuclear plants, radiotherapy, and aerospace gradually. Low dose hyper-radiosensitivity response of low Linear Energy Transfer (LET) irradiation on the cell survival has become a matter of great interest since its discovery, but a few research have been done on this response induced by neutron irradiation. To investigate this response induced by neutron irradiation, Caenorhabditis elegans (C. elegans) was irradiated by neutron irradiation. The surviving fraction of C. elegans on the 12th day after irradiation was analyzed, which showed a hyper-radiosensitive response at low doses and followed by an increase in survival fraction at slightly higher doses. The finding of this work that neutron irradiation decreased the surviving fraction in a non-dose-dependent manner was different from previous low-LET irradiation studies. To understand the experimental results, a DNA damage-repair model was introduced. By comparing experimental results with theoretical analyses, we suggest that the low dose hyper-radiosensitivity response of neutron irradiation may possible related to different radiation types and DNA damage recognition proteins and immune system of C. elegans.

Gas chromatography-mass spectrometry analysis of essential oils from five parts of Chaihu (Radix Bupleuri Chinensis).

OBJECTIVE: To analyze the essential oils from flowers, leaves, stems, roots, and fruits of Chaihu (Radix Bupleuri Chinensis). METHODS: We extracted essential oils from different parts of Chaihu (Radix Bupleuri Chinensis) using a steam distillation method. The essential oils were analyzed by gas chromatography-mass spectrometry (GC-MS). Data were collected in full scan mode (m/z 60-600). Volatile components were identified based on their retention indices and by comparing their mass spectra with those in the National Institute of Standards and Technology 2005 database, assisted by tandem mass spectrometry information. The relative content of each constituent was determined by area normalization. RESULTS: We identified 111 components, of which 12 were common to all 5 parts, 30 were found only in roots, 14 were found only in flowers, 6 were found only in leaves, 4 were found only in stems, and 17 were found only in fruits. CONCLUSION: Our results show that the stems, flowers, leaves, and fruits of Chaihu (Radix Bupleuri Chinensis) contain a high concentration of essential oils, and that the exact composition of the essential oils differs among the plant parts. To develop new medicines and make full use of the Chaihu (Radix Bupleuri Chinensis) resource, it is important to characterize the essential oils from different parts of the plant. In future research, it will be important to determine the pharmacological effects of the various components and the essential oil mixtures.

Cell-cycle-dependent variations in the FTIR spectroscopy of HeLa cells treated with trichostatin A.

It is quite complex to evaluate the mechanism of action for antitumor drugs on cancer cells. Studies have pointed out that there is an unique advantage of Fourier transform infrared spectrum to obtain a fingerprint of all molecules present in the cells when cancer cells were exposed to anti-cancer drugs. Trichostatin A (TSA) is a most potent reversible inhibitor of mammalian histone deacetylases. It can inhibit cancer cell growth in vitro and in vivo. In the present study, HeLa cells were exposed to 0, 50, 100, 200, 300 and 400 nmol x L(-1) TSA, and FTIR spectra were applied to evaluate the effect of TSA on cancer cells. Results show that there is some significant relationship between the changes in FTIR absorption and cell cycle arresting. On the other hand, this investigation shows that the concentration of TSA had to be more than 200 nmol x L(-1) in order to ensure A1080 cm(-1)/A1540 cm(-1) > or = 1 for inhibiting cell proliferation.

[FTIR spectroscopic analysis of HeLa cell irradiated by low-energy ions].

In the present paper, low-energy N+ ions produced by low-energy ionic radiometer were used to simulate low-energy ions in astrospace implanting HeLa cell. Then, the effect and mechanism of low-energy ion on the cell were studied with FTIR spectroscopic analysis. In this study, low-energy ions were produced and accelerated in vacuum, and cells would be affected by vacuum when they were implanted by low-energy ions, so mineral oil was used to protect cells from water evaporation. Cells were collected after being implanted, then the change in the content and constructional form in cellular macromolecule with infrared spectrometry. Result indicated that the spectroscopic peak position of differently worked cells was obviously different as compared to the control cell (3300 cm(-1)). Spectroscopic peak position of all samples except implanting 5 x 10(14) N+ x cm(-2) removed to longer wavelength, and the peak position in vacuum of 2 x 10(15) N+ x cm(-2) sample moved to 3420 cm(-1). In addition, the 1378 and 2360 cm(-1) spectroscopic peak positions in control cell all moved to longer wavelength in every worked group. In a word, FTIR spectroscopic analysis indicates that low-energy ion implantation could arouse change in nucleic acid or protein in HeLa cell.